Positronium lifetime in polymers

A model describing the relationship between the ortho--positronium lifetime and the volume of a void, located in a synthetic zeolite, is analyzed. Our idea, which allows us to take into account the effects of temperature, comprises the introduction of a non--hermitian term in the Hamiltonian, which accounts for the annihilation of the ortho--positronium. The predictions of the present model are also confronted against an already known experimental result.Comment: Accepted in Journal of Chemical Physic

A MIXED METHODS APPROACH TO THE STUDY OF PELL RECIPIENTS\u27 FORMATION OF ACADEMIC CAPITAL AND THE INFLUENCE OF INSTITUTIONAL AGENTS

The purpose of this explanatory sequential study was to identify factors associated with Pell grant recipients\u27 persistence in a community college setting and to understand the influence of institutional actors on the formation of academic capital. Students completed a survey designed to measure the formation of students\u27 academic capital (St. John et al., 2011; Winkler & Sriram, 2015). Then, survey participants participated in interviews to examine the influence of institutional actors and the role they play in the development of academic capital (Stanton-Salazar, 1997; Stanton-Salazar, 2011). Three meta-inferences emerged from the data that provided an overall explanation of the factors relevant to the persistence of Pell recipients. First, it was clear that financial aid processes generated enduring and existential barriers to the participants, creating feelings of powerlessness and a lack of agency over the process. Second, there was evidence of emotional distress caused by challenging situations during the participants\u27 college experience. Through the encouragement and support of institutional agents, the participants overcame their difficulties; they developed confidence which grounded them in the academic community. Lastly, the third meta-inference revealed how the participants relied on their academic capital to develop their self-advocacy in a college setting. By using the information and resources mobilized by institutional agents, the participants employed more control over their college experience

Older and wiser? Men’s and women’s accounts of drinking in early mid-life

Most qualitative research on alcohol focuses on younger rather than older adults. To explore older people’s relationship with alcohol, we conducted eight focus groups with 36 men and women aged 35 to 50 years in Scotland, UK. Initially, respondents suggested that older drinkers consume less alcohol, no longer drink to become drunk and are sociable drinkers more interested in the taste than the effects of alcohol. However, as discussions progressed, respondents collectively recounted recent drunken escapades, challenged accounts of moderate drinking, and suggested there was still peer pressure to drink. Some described how their drinking had increased in mid-life but worked hard discursively to emphasise that it was age and stage appropriate (i.e. they still met their responsibilities as workers and parents). Women presented themselves as staying in control of their drinking while men described going out with the intention of getting drunk (although still claiming to meet their responsibilities). While women experienced peer pressure to drink, they seemed to have more options for socialising without alcohol than did men. Choosing not to drink alcohol is a behaviour that still requires explanation in early mid-life. Harm reduction strategies should pay more attention to drinking in this age group

How actionable are staff behaviours specified in policy documents? A document analysis of protocols for managing deteriorating patients

BACKGROUND: To optimise care of deteriorating patients, healthcare organisations have implemented rapid response systems including an "afferent" and "efferent" limb. Afferent limb behaviours include monitoring vital signs and escalating care. To strengthen afferent limb behaviour and reduce adverse patient outcomes, the National Early Warning Score was implemented in the UK. There are no published reports of how National Early Warning Score guidance has translated into trust-level deteriorating patient policy and whether these documents provide clear, actionable statements guiding staff. AIM: To identify how deteriorating patient policy documents provide "actionable" behavioural instruction for staff, responsible for actioning the afferent limb of the rapid response system. DESIGN: A structured content analysis of a national guideline and local policies using a behaviour specification framework. METHODS: Local deteriorating patient policies were obtained. Statements of behaviour were extracted from policies; coded using a behaviour specification framework: Target, Action, Context, Timing and Actor and scored for specificity (1 = present, nonspecific; 2 = present, specific). Frequencies and proportions of statements containing elements of the Target, Action, Context, Timing and Actor framework were summarised descriptively. Reporting was guided by the COREQ checklist. RESULTS: There were more statements related to monitoring than escalation behaviour (65% vs 35%). Despite high levels of clear specification of the action (94%) and the target of the behaviour (74%), context, timing and actor were poorly specified (37%, 37% and 33%). CONCLUSION: Delay in escalating deteriorating patients is associated with adverse outcomes. Some delay could be addressed by writing local protocols with greater behavioural specificity, to facilitate actionability. RELEVANCE TO CLINICAL PRACTICE: Numerous clinical staff are required for an effective response to patient deterioration. To mitigate role confusion, local policy writers should provide clear specification of the actor. As the behaviours are time-sensitive, clear specification of the time frame may increase actionability of policy statements for clinical staff

Conceptualising quality of life for older people with aphasia

Background: There is an increasing need in speech and language therapy for clinicians to provide intervention in the context of the broader life quality issues for people with aphasia. However, there is no descriptive research that is explicitly focused on quality of life (QoL) from the perspectives of older people with aphasia. Aims: The current study explores how older people with chronic aphasia who are living in the community describe their QoL in terms of what contributes to and detracts from the quality in their current and future lives. The study is descriptive in nature, and the purpose is to conceptualize the factors that influence QoL. Methods & Procedures: Thirty older participants (16 women, 14 men) with mild to moderate aphasic impairment took part. All participants had adequate communication skills to participate: demonstrating reliable yes/no response and moderate auditory comprehension ability. Participants were interviewed in their own homes using six brief unprompted open questions about QoL, in a structured interview. The first five questions were drawn from previous gerontological research (Farquhar, 1995), and a sixth question specifically targeting communication was added. Content analysis was used, identifying discrete units of data and then coding these into concepts and factors. Additional demographic information was collected, and participants’ mood on day of interviewing was assessed using the Geriatric Depression Scale (Sheikh & Yesavage, 1986). Outcomes & Results: Activities, verbal communication, people, and body functioning were the core factors in QoL for these participants, and they described how these factors both contributed quality in life as well as detracted from life quality. Other factors that influenced QoL included stroke, mobility, positive personal outlook, in/dependence, home and health. Whilst the findings are limited by the lack of probing of participants’ responses, the study does present preliminary evidence for what is important in QoL to older people with aphasia. Conclusions: Quality of life for older people with predominantly mild to moderate chronic aphasia who are living in the community is multifactorial in nature. Some factors lie within the remit of speech and language therapy, some lie beyond the professional role, but all are relevant for consideration in rehabilitation and community practice. Further qualitative research is implicated to better understand QoL with aphasia, using in-depth interviewing with a broader range of people with aphasia

Human immunodeficiency virus rebound after suppression to < 400 copies/mL during initial highly active antiretroviral therapy regimens, according to prior nucleoside experience and duration of suppression

This study evaluated 1433 human immunodeficiency virus (HIV)-infected patients starting highly active antiretroviral therapy (HAART), 409 (28%) of whom had prior nucleoside experience and achieved an HIV load of <400 copies/mL by 24 weeks of therapy. Three hundred seven patients experienced virus rebound during a total of 2773.3 person-years of follow-up. There was a higher rate of virus rebound among the patients with pre-HAART nucleoside experience (relative hazard [RH], 2.86; 95% confidence interval, 2.22-3.84; P < .0001) and a decreasing rate of virus rebound with increasing duration of virus suppression (i.e., time since achieving a virus load of <400 HIV RNA copies/mL) among both the nucleoside-experienced and naive patients (P < .0001), but the difference between the groups persisted into the third year of follow-up (P = .0007). Even patients who had experienced <2 months of nucleoside therapy before beginning HAART had an increased risk of virus rebound (RH, 1.95; P = .009). It appears that only a small period of pre-HAART nucleoside therapy is sufficient to confer a disadvantage, in terms of risk of virus rebound, that persists for several years

Just keep grazing: Parrotfish grazing and dietary selectivity in the Florida Keys

Parrotfish have indirect positive effects on corals by grazing on macroalgae that competes for substrate space with corals. Parrotfish can also have a negative impact on corals by feeding on live coral. Feeding preferences are correlated to jaw morphology in parrotfishes. This study examined the feeding selectivity for two genera of parrotfish (Scarus and Sparisoma) in the Florida Keys to determine the impacts they have on coral reefs. On 14 reefs, fish censuses, behavioral surveys and substrate composition analysis were preformed to calculate selectivity indices for the various substrate types. The indices showed that parrotfish do exhibit selective feeding. Scarus had a significantly higher preference for turf and Sparisoma had a significantly higher preference for macroalgae. These results support life history theory that Scarus are excavators and Sparisoma are grazers as predicted by their jaw morphology. This project was partially supported by the Creative Inquiry program